v4.19.13 snapshot.
diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/sysdev/scom.c
new file mode 100644
index 0000000..0f6fd5d
--- /dev/null
+++ b/arch/powerpc/sysdev/scom.c
@@ -0,0 +1,236 @@
+/*
+ * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
+ * <benh@kernel.crashing.org>
+ * and David Gibson, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <asm/debugfs.h>
+#include <asm/prom.h>
+#include <asm/scom.h>
+#include <linux/uaccess.h>
+
+const struct scom_controller *scom_controller;
+EXPORT_SYMBOL_GPL(scom_controller);
+
+struct device_node *scom_find_parent(struct device_node *node)
+{
+ struct device_node *par, *tmp;
+ const u32 *p;
+
+ for (par = of_node_get(node); par;) {
+ if (of_get_property(par, "scom-controller", NULL))
+ break;
+ p = of_get_property(par, "scom-parent", NULL);
+ tmp = par;
+ if (p == NULL)
+ par = of_get_parent(par);
+ else
+ par = of_find_node_by_phandle(*p);
+ of_node_put(tmp);
+ }
+ return par;
+}
+EXPORT_SYMBOL_GPL(scom_find_parent);
+
+scom_map_t scom_map_device(struct device_node *dev, int index)
+{
+ struct device_node *parent;
+ unsigned int cells, size;
+ const __be32 *prop, *sprop;
+ u64 reg, cnt;
+ scom_map_t ret;
+
+ parent = scom_find_parent(dev);
+
+ if (parent == NULL)
+ return 0;
+
+ /*
+ * We support "scom-reg" properties for adding scom registers
+ * to a random device-tree node with an explicit scom-parent
+ *
+ * We also support the simple "reg" property if the device is
+ * a direct child of a scom controller.
+ *
+ * In case both exist, "scom-reg" takes precedence.
+ */
+ prop = of_get_property(dev, "scom-reg", &size);
+ sprop = of_get_property(parent, "#scom-cells", NULL);
+ if (!prop && parent == dev->parent) {
+ prop = of_get_property(dev, "reg", &size);
+ sprop = of_get_property(parent, "#address-cells", NULL);
+ }
+ if (!prop)
+ return NULL;
+ cells = sprop ? be32_to_cpup(sprop) : 1;
+ size >>= 2;
+
+ if (index >= (size / (2*cells)))
+ return 0;
+
+ reg = of_read_number(&prop[index * cells * 2], cells);
+ cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
+
+ ret = scom_map(parent, reg, cnt);
+ of_node_put(parent);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(scom_map_device);
+
+#ifdef CONFIG_SCOM_DEBUGFS
+struct scom_debug_entry {
+ struct device_node *dn;
+ struct debugfs_blob_wrapper path;
+ char name[16];
+};
+
+static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ struct scom_debug_entry *ent = filp->private_data;
+ u64 __user *ubuf64 = (u64 __user *)ubuf;
+ loff_t off = *ppos;
+ ssize_t done = 0;
+ u64 reg, reg_cnt, val;
+ scom_map_t map;
+ int rc;
+
+ if (off < 0 || (off & 7) || (count & 7))
+ return -EINVAL;
+ reg = off >> 3;
+ reg_cnt = count >> 3;
+
+ map = scom_map(ent->dn, reg, reg_cnt);
+ if (!scom_map_ok(map))
+ return -ENXIO;
+
+ for (reg = 0; reg < reg_cnt; reg++) {
+ rc = scom_read(map, reg, &val);
+ if (!rc)
+ rc = put_user(val, ubuf64);
+ if (rc) {
+ if (!done)
+ done = rc;
+ break;
+ }
+ ubuf64++;
+ *ppos += 8;
+ done += 8;
+ }
+ scom_unmap(map);
+ return done;
+}
+
+static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ struct scom_debug_entry *ent = filp->private_data;
+ u64 __user *ubuf64 = (u64 __user *)ubuf;
+ loff_t off = *ppos;
+ ssize_t done = 0;
+ u64 reg, reg_cnt, val;
+ scom_map_t map;
+ int rc;
+
+ if (off < 0 || (off & 7) || (count & 7))
+ return -EINVAL;
+ reg = off >> 3;
+ reg_cnt = count >> 3;
+
+ map = scom_map(ent->dn, reg, reg_cnt);
+ if (!scom_map_ok(map))
+ return -ENXIO;
+
+ for (reg = 0; reg < reg_cnt; reg++) {
+ rc = get_user(val, ubuf64);
+ if (!rc)
+ rc = scom_write(map, reg, val);
+ if (rc) {
+ if (!done)
+ done = rc;
+ break;
+ }
+ ubuf64++;
+ done += 8;
+ }
+ scom_unmap(map);
+ return done;
+}
+
+static const struct file_operations scom_debug_fops = {
+ .read = scom_debug_read,
+ .write = scom_debug_write,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
+ int i)
+{
+ struct scom_debug_entry *ent;
+ struct dentry *dir;
+
+ ent = kzalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+
+ ent->dn = of_node_get(dn);
+ snprintf(ent->name, 16, "%08x", i);
+ ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
+ ent->path.size = strlen((char *)ent->path.data);
+
+ dir = debugfs_create_dir(ent->name, root);
+ if (!dir) {
+ of_node_put(dn);
+ kfree(ent->path.data);
+ kfree(ent);
+ return -1;
+ }
+
+ debugfs_create_blob("devspec", 0400, dir, &ent->path);
+ debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
+
+ return 0;
+}
+
+static int scom_debug_init(void)
+{
+ struct device_node *dn;
+ struct dentry *root;
+ int i, rc;
+
+ root = debugfs_create_dir("scom", powerpc_debugfs_root);
+ if (!root)
+ return -1;
+
+ i = rc = 0;
+ for_each_node_with_property(dn, "scom-controller") {
+ int id = of_get_ibm_chip_id(dn);
+ if (id == -1)
+ id = i;
+ rc |= scom_debug_init_one(root, dn, id);
+ i++;
+ }
+
+ return rc;
+}
+device_initcall(scom_debug_init);
+#endif /* CONFIG_SCOM_DEBUGFS */